Juloski Jelena, Apicella Davide, Ferrari Marco
Department of Medical Biotechnologies, University of Siena, Policlinico Le Scotte, Viale Bracci, 53100 Siena, Italy; Clinic for Pediatric and Preventive Dentistry, School of Dentistry, University of Belgrade, Doktora Subotica 11, 11000 Belgrade, Serbia.
Department of Medical Biotechnologies, University of Siena, Policlinico Le Scotte, Viale Bracci, 53100 Siena, Italy; Department of Oral and Maxillofacial Sciences, University "Federico II", Policlinico Via Pansini, 5, 80131 Naples, Italy.
Dent Mater. 2014 Dec;30(12):1304-15. doi: 10.1016/j.dental.2014.09.004. Epub 2014 Oct 8.
To evaluate via finite element analysis the effect of different ferrule heights on stress distribution within each part of a maxillary first premolar (MFP) restored with adhesively luted glass fiber-reinforced resin (GFRR) posts and a ceramic crown.
The solid models consisted of MFP, periodontal ligament and the corresponding alveolar bone process. Four models were created representing different degrees of coronal tissue loss (0mm, 1mm, 2mm and 3mm of ferrule height). First set of computing runs was performed for in vivo FE-model validation purposes. In the second part, a 200-N force was applied on the buccal cusp directed at 45° to the longitudinal axis of the tooth. Principal stresses values and distribution were recorded within root, abutment, posts, crown and related adhesive interfaces.
All FE-models showed similar stress distribution within roots, with highest stress present in the chamfer area. In composite abutments higher stress was observed when no ferrule was present compared to ferruled FE-models. Stress distribution within crown and GFRR posts did not differ among the models. Stress values at the adhesive interfaces decreased with increasing ferrule height.
The stress state at abutment-crown and post-root interfaces was very close to their strength, when ferrule was not present. Similarly, higher ferrule produced more favorable stress distribution at post-abutment and abutment-root interfaces. Endodontically treated teeth with higher ferrule exhibit lower stress at adhesive interfaces that may be expected to lower the probability of clinical failure.
通过有限元分析评估不同桩核高度对上颌第一前磨牙(MFP)各部分应力分布的影响,该磨牙采用粘结式玻璃纤维增强树脂(GFRR)桩和陶瓷冠修复。
实体模型包括MFP、牙周韧带和相应的牙槽骨突。创建了四个模型,分别代表不同程度的冠部组织丧失(桩核高度为0mm、1mm、2mm和3mm)。第一组计算运行是为了进行体内有限元模型验证。在第二部分中,在颊尖上施加一个200N的力,该力与牙齿的纵轴成45°角。记录牙根、基牙、桩、冠及相关粘结界面内的主应力值和分布。
所有有限元模型在牙根内均显示出相似的应力分布,在肩台区域应力最高。与有桩核的有限元模型相比,在无桩核的复合基牙中观察到更高的应力。模型之间冠和GFRR桩内的应力分布没有差异。粘结界面处的应力值随着桩核高度的增加而降低。
当没有桩核时,基牙-冠和桩-根界面处的应力状态非常接近其强度。同样,更高的桩核在桩-基牙和基牙-根界面处产生更有利的应力分布。桩核较高的根管治疗牙齿在粘结界面处表现出较低的应力,这可能会降低临床失败的概率。